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In advance of taking my car back to a shell and after Andrews unfortunate distortion experience I will be making a jig/transport/dipping/rollover frame. Inspiration is from the frame Barry made for Jonathon’s E Type.
I’ve got the dimensional drawing from the manual but I’m struggling to work out the vertical dimension from the reference plane of the front wishbone mountings.
I can see it’s slightly less than 108mm from the position of the rear ones but it’s not explicitly stated, unless I’m missing something.
It’s the dimension with the question mark inside the dotted circle shown on the marked up drawing attached.
I can't help you Gary, but I think you have missed nothing!
How do you position the red datum line off that drg? Seems to come off the door sill top.
I interpret that drg as 108mm for the rear front wishbone mounting and then 3 deg tilt and using some trigonometry, you can set the dimension of the rear front 'bone mounting off the red datum as you know the centres of the mounting holes already. I would have thought the draftsman would have done that so the jigs could be made using dimensions rather than the trickier angles.
Seeing as your car is straight I would come off the current suspension points to pick up some clear positions with the rear engine mounts and banana arm /torque tube points. Good beefy positions easy to get at with the mechanicals out and giving access to the inevitable areas for welding, ie torque tube ends etc.
If it counts, when I did my sills and outer floor edge replacements, front suspension pan etc I had no jigs but did it all by spirit levels etc.
After my shunt at Shelsley about 4 years after the rebuild, the car went on a jig to straighten the front NS corner and the shell was a dead fit to the cellette. Body shop was very complimentary.
I have done 2 MGB's before the 911 using the same precautions and all were good. The surgery was much the same, one a GT one a roadster. I tack welded a simple 1" thin wall box section tube across the roadster's door openings etc to brace the open shell. It had all it's running gear still in the shell, so did the GT.
73T 911 Coupe, road/hillclimber 3.2L
Lola t 492 / 3.2 hillclimb racer
Boxster 987 Gen II 2.9
Thanks Graham, I spotted the 3deg but hoped there was an easier answer.
My car may not be straight, but it does drive ok and the doors shut so I’d like to keep it that way!
The reference plane is just that I think, it doesn’t align with anything.
I’m drawing the frame up on CAD hence trying for real dimensions.
Obviously in real life I’ll have to allow for a degree of adjustment to meet the car as I don’t have a jig to make the jig on! It would also be good to see how straight it is, even if I don’t do anything about it.
Hi Gary, I can get you this dimension off of my Celette if that helps. On the jig, it's easy enough to measure the relative vertical difference between A-arm front mounts and A-arm rear mount, which will tell you exactly how different to 108mm from reference plane it should be.
Do you need the position of all three front A-arm mounts? They are not in the same plane XY, but are inclined at differing Z-heights (lowest is the one towards the centre of the car).
Happy to measure it in the shop for you this afternoon, just confirm for me it's only the lowest (innermost) front mounting you need, as per your green line, or all three. Feel free to give me a ring if you need any other dims.
All measurements to centre-line of fixing holes, +/- 0.5mm in Z on my measurement method: steel rule measure to Celette platform reference plane, then datum'd to the '108' rear fixing.
Inboard front mount (the one marked 'X' in the dwg): 111mm from the red reference line
Foremost front mount: 96mm from the red reference line
Outboard front mount (the highest one of the three): 91mm from the red reference line.
